cold feet vs faintheartedness

cold feet

noun
  • A feeling of nervousness or anxiousness causing one to reconsider a decision about an upcoming event. 

  • Used other than figuratively or idiomatically: see cold, feet. 

faintheartedness

noun
  • The quality or state of being fainthearted. 

How often have the words cold feet and faintheartedness occurred in a corpus of books? (source: Google Ngram Viewer )